F-doped O3-NaNi1/3Fe1/3Mn1/3O2 as high-performance cathode materials for sodium-ion batteries

作者：Zhang, Qin; Huang, Yangyang; Liu, Yi; Sun, Shixiong; Wang, Kun; Li, Yuyu; Li, Xiang; Han, Jiantao^*; Huang, Yunhui

来源：Science China-Materials, 2017, 60(7): 629-636.

DOI：10.1007/s40843-017-9045-9

• O-3-type
• NaNi1/3Fe1/3Mn1/3O2
• F-doping
• sodium-ion batteries

The F-doped O3-type NaNi1/3Fe1/3Mn1/3O2-xFx (x = 0, 0.005, 0.01, 002 and noted as NFM-F0, NFM-F0.005, NFM-F0.01, NFM-F0.02, respectively, united as NFM-Fs) cathode materials were investigated systematically. The rate performance and capacity retention of the O3-type cathode materials are significantly improved as a function of specific F-doping levels. Optimum performance is achieved in the NFM-F0.01 material having a capacity of similar to 110 mA hg(-1) at a current density of 150 mAg(-1) after 70 cycles. The results indicate that the binding energy of oxygen changes as a result of F-doping, and in addition, F-doping results in changes to the stoichiometry of Mn3+/Mn4+, which stabilizes the O3-type layered structure, thus allowing cycling performance to be improved. However, NFM-F0.02, having a higher F-doping level, retains a high capacity retention, although a slight loss is observed. The results suggest there is an optimum F-doping level for the NFM-F system to deliver enhanced cycling performance.

• 出版日期2017-7
• 单位华中科技大学